Jason-1 will replace the old Topex/Poseidon satellite. Here
is what is happening.

In August of 1992, a joint venture between the United States
and France
(check out this site to brush up on your French!) sent the TOPEX/POSEIDON
satellite into Earth orbit. TOPEX is an acronym that stands for Ocean Topography
Experiment. The name TOPEX comes from the US contribution to the project.
Poseidon was
the Greek God who held power over the oceans. The name Poseidon comes from
the French contribution to the project.

TOPEX/POSEIDON measures sea level with amazing accuracy.
To find out how something 1,336 km above the planet can measure the rise and
fall of the ocean to within a centimeter check out our Satellites
page. The T/P has other uses as well. It helps warn meteorologists, the people
who study the weather, about El Niño and La Niña and other weather
patterns. It is helpful in ship routing, commercial fishing, sailing, hurricane
prediction, studying ocean circulation, climate forecasting and many other
things you wouldn't even think of.

T/P was only supposed to last a three years, but it was
working so well that in 1995 it was given an extension. After 10 years of
service, it is being replaced by Jason-1, the best altimeter satellites there
is. It will give near-time data with a delay of only 3 hours. That means 3
hours after Jason-1 has measured something, the scientists here on Earth will
know just what it saw.

The Jason-1 satellite was named for a hero from Greek mythology.
Jason and the
Argonauts, the crew of his ship the Argo, went on adventures in search
of the Golden Fleece. The satellite was named after Jason because he was a
sailor fascinated by the ocean and because he worked with many different kinds
of people. Together they went on difficult and dangerous adventures for a
good cause just like the two groups, NASA/JPL
and CNES,
working on Jason-1. The satellite is called Jason-1 because it is hoped to
be the first in a 20 year long series of Jason satellite missions.

The Jason-1 satellite mission is totally unrelated to The
Jason Project, just in case you were confused.